In the installation of residential electrical wiring, there is seldom a need for complex electronic measuring instruments. On the contrary, the functions that are most necessary are a means of determining if a particular point in the system carries 110-volt electricity, and whether there is simple conductivity between two points in the system. In addition, it is necessary to provide illumination, since a great deal of the work is accomplished in recesses and dark areas. Attempts have been made in the past to provide all three of these functions in one unit, particularly in a flashlight. One difficulty has always been that it is difficult to make contact with two leads and still be able to observe the bulb in the flashlight, particularly if the flashlight is at the same time being used to illuminate the work area. The difficulty with the prior art devices has been that, when the contacts between the leads and the two points whose voltage is being investigated are released, the indicating lamp (which is the bulb of the flashlight) turns off. These and other difficulties experienced with the prior art devices have been obviated in a novel manner by the present invention.
It is, therefore, an outstanding object of the invention to provide a flashlight capable of operating in a voltage mode with a memory.
Another object of this invention is the provision of a flashlight, including the three functions of lighting, voltage indicating, and conductivity indicating in one unit.
It is another object of the instant invention to provide a flashlight having leads to indicate the presence of voltage between two points by lighting the bulb of the flashlight, the bulb remaining in lighted condition even after contact by the leads has been removed.
A still further object of the invention is the provision of a flashlight for indicating the presence of voltage, wherein the presence of voltage lights up the bulb, the bulb remaining lit until positively released by the user.
It is a further object of the invention to provide a flashlight in which the conventional on-and-off switch is also used to convert from voltage mode to conductivity mode.
It is still a further object of the present invention to provide a flashlight having leads for indicating voltage or conductivity which, when wrapped around the housing and connected together, permit the apparatus to be used for lighting purposes in the conventional manner.
With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.